Blog: Meganne Christian

Meganne Christian from CNR has been busy in the lab preparing sample wick for the parabolic flight in November!

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The summer is over but things are still hot in the lab, where we've been working hard on new materials for the loop heat pipe project.

I'm a postdoctoral researcher at the National Research Council of Italy (CNR) and I first got involved with this project two years ago at a Graphene Flagship work package meeting in Manchester. Researchers at the Université Libre de Bruxelles (ULB) were looking for ways to coat their porous wicks with graphene and the structures they showed looked remarkably like the graphene foams that I had been making in our lab. I thought it should be possible to adapt the procedure, so we shared our ideas and the collaboration began.

About a month ago you heard from Yarjan at the Cambridge Graphene Centre, who is working on depositing graphene inks inside the pores of metal wicks to create 3D architectures that can enhance their performance in a loop heat pipe. The results have been very promising, but one of the challenges lies in depositing graphene all the way through to the centre of the wick. A technique that could help with this is chemical vapour deposition, where the graphene is grown from a gas precursor which can easily make its way inside the micro-sized pores of the material.

Usually graphene is grown in this way on metals like copper, nickel, platinum and germanium but the wicks for the heat pipes are made of stainless steel, which hasn't been studied a lot for graphene growth in the past. That's no problem though, here at CNR in Bologna we have refined the procedure and produced a uniform coating of graphene right through to the centre of the wicks. Unlike using graphene inks, we are not able to form nice 3D architectures with this technique, so we have to do some electrochemistry afterwards to "damage" the graphene a little and make it expand.

Ultimately the best results are going to come from an integrated approach using both what we have learnt here in Bologna and what our colleagues have learnt in Cambridge!

Next on the agenda is some ground testing of the materials that we have made so far. In the last blogpost you heard a bit about that from Vanja at ULB. I'm looking forward to working on the tests with her and her colleagues to prepare the final prototypes that will go flying with us on the parabolic flight!